Correct Answer: + and ×

Solution : Given:
16 + 4 ÷ 2 × 12 − 4 = 40

Replace the given signs in the question one by one with the original signs in the given equation.
First option: + and ×
⇒ 16 × 4 ÷ 2 + 12 − 4 = 40
= 32 + 8
= 40
Second option: + and −
⇒ 16 − 4 ÷ 2 × 12 + 4 = 40
= 16 − 24 + 4
= −4 ≠ 40
Third option: ÷ and ×
⇒ 16 + 4 × 2 ÷ 12 − 4 = 40
= 16 + 0.67 − 4
= 12.67 ≠ 40
Fourth option: ÷ and +
⇒ 16 ÷ 4 + 2 × 12 − 4 = 40
= 4 + 24 − 4
= 24 ≠ 40

So, only the first option satisfies the R.H.S. of the given equation. Hence, the first option is correct.